1. Field of the Invention
The present invention relates to a vehicle-height adjustment apparatus of a motorcycle.
2. Description of the Related Art
Desirably, the vehicle height of motorcycles is set relatively low such that even short riders can easily set their feet on ground, as this prevents the motorcycles from falling down at the time of stopping. On the other hand, motorcycles are required to have a certain degree of vehicle height from the viewpoint of bank angles, shock absorption, or the like at the time of running. In addition, some motorcycles for the market in America are designed to have a low vehicle height when they are not running so that they meet market needs in terms of appearance.
In view of this, there has been proposed the vehicle-height adjustment apparatus of a motorcycle as described in Japanese Examined Patent Publication No. H8-22680. The vehicle-height adjustment apparatus has a damper tube, a piston rod, a hydraulic jack, a suspension spring, a hydraulic pump, and a switching valve. The damper tube is provided on one side of a vehicle body and an axle. The piston rod is provided on the other side of the vehicle body and the axle and performs extension and compression movements relative to the damper tube by sliding in a hydraulic chamber inside the damper tube. The hydraulic jack is provided on one side of the damper tube and the piston rod. The suspension spring is interposed between a spring bearing supported by a plunger inserted in the jack chamber of the hydraulic jack and a spring bearing provided on the other side of the damper tube and the piston rod. The hydraulic pump is caused to perform a pumping operation by the extension and compression movements of the piston rod relative to the damper tube to supply and drain the oil of the hydraulic chamber inside the damper tube to and from the jack chamber of the hydraulic jack. The switching valve is closed such that the operating oil supplied to the jack chamber of the hydraulic jack is stopped, or is opened such that the operating oil is discharged. The vehicle-height adjustment apparatus is capable of adjusting a vehicle height by the tension and compression movements of the piston rod relative to the damper tube.
[Patent Literature 1] Japanese Examined Patent Publication No. H8-22680